src/Protocol/ActivityPub/Processor.php

   1 <?php
   2 /**
   3  * @file src/Protocol/ActivityPub/Processor.php
   4  */
   5 namespace Friendica\Protocol\ActivityPub;
   6
   7 use Friendica\Database\DBA;
   8 use Friendica\Content\Text\HTML;
   9 use Friendica\Core\Config;
  10 use Friendica\Core\Logger;
  11 use Friendica\Core\Protocol;
  12 use Friendica\Model\Contact;
  13 use Friendica\Model\APContact;
  14 use Friendica\Model\Item;
  15 use Friendica\Model\Event;
  16 use Friendica\Model\Term;
  17 use Friendica\Model\User;
  18 use Friendica\Protocol\ActivityPub;
  19 use Friendica\Util\DateTimeFormat;
  20 use Friendica\Util\JsonLD;
  21 use Friendica\Util\Strings;
  22
  23 /**
  24  * ActivityPub Processor Protocol class
  25  */
  26 class Processor
  27 {
  28         /**
  29          * Converts mentions from Pleroma into the Friendica format
  30          *
  31          * @param string $body
  32          *
  33          * @return string converted body
  34          */
  35         private static function convertMentions($body)
  36         {
  37                 $URLSearchString = "^\[\]";
  38                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
  39
  40                 return $body;
  41         }
  42
  43         /**
  44          * Replaces emojis in the body
  45          *
  46          * @param array $emojis
  47          * @param string $body
  48          *
  49          * @return string with replaced emojis
  50          */
  51         public static function replaceEmojis($body, array $emojis)
  52         {
  53                 foreach ($emojis as $emoji) {
  54                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
  55                         $body = str_replace($emoji['name'], $replace, $body);
  56                 }
  57                 return $body;
  58         }
  59
  60         /**
  61          * Constructs a string with tags for a given tag array
  62          *
  63          * @param array   $tags
  64          * @param boolean $sensitive
  65          * @param array   $implicit_mentions List of profile URLs to skip
  66          * @return string with tags
  67          */
  68         private static function constructTagString($tags, $sensitive, array $implicit_mentions)
  69         {
  70                 if (empty($tags)) {
  71                         return '';
  72                 }
  73
  74                 $tag_text = '';
  75                 foreach ($tags as $tag) {
  76                         if (in_array(defaults($tag, 'type', ''), ['Mention', 'Hashtag']) && !in_array($tag['href'], $implicit_mentions)) {
  77                                 if (!empty($tag_text)) {
  78                                         $tag_text .= ',';
  79                                 }
  80
  81                                 $tag_text .= substr($tag['name'], 0, 1) . '[url=' . $tag['href'] . ']' . substr($tag['name'], 1) . '[/url]';
  82                         }
  83                 }
  84
  85                 /// @todo add nsfw for $sensitive
  86
  87                 return $tag_text;
  88         }
  89
  90         /**
  91          * Add attachment data to the item array
  92          *
  93          * @param array $attachments
  94          * @param array $item
  95          *
  96          * @return array array
  97          */
  98         private static function constructAttachList($attachments, $item)
  99         {
 100                 if (empty($attachments)) {
 101                         return $item;
 102                 }
 103
 104                 foreach ($attachments as $attach) {
 105                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
 106                         if ($filetype == 'image') {
 107                                 $item['body'] .= "\n[img]" . $attach['url'] . '[/img]';
 108                         } else {
 109                                 if (!empty($item["attach"])) {
 110                                         $item["attach"] .= ',';
 111                                 } else {
 112                                         $item["attach"] = '';
 113                                 }
 114                                 if (!isset($attach['length'])) {
 115                                         $attach['length'] = "0";
 116                                 }
 117                                 $item["attach"] .= '[attach]href="'.$attach['url'].'" length="'.$attach['length'].'" type="'.$attach['mediaType'].'" title="'.defaults($attach, 'name', '').'"[/attach]';
 118                         }
 119                 }
 120
 121                 return $item;
 122         }
 123
 124         /**
 125          * Updates a message
 126          *
 127          * @param array $activity Activity array
 128          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 129          */
 130         public static function updateItem($activity)
 131         {
 132                 $item = Item::selectFirst(['uri', 'parent-uri', 'gravity'], ['uri' => $activity['id']]);
 133                 if (!DBA::isResult($item)) {
 134                         Logger::warning('Unknown item', ['uri' => $activity['id']]);
 135                         return;
 136                 }
 137
 138                 $item['changed'] = DateTimeFormat::utcNow();
 139                 $item['edited'] = $activity['updated'];
 140                 $item['title'] = HTML::toBBCode($activity['name']);
 141                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
 142
 143                 $content = HTML::toBBCode($activity['content']);
 144                 $content = self::replaceEmojis($content, $activity['emojis']);
 145                 $content = self::convertMentions($content);
 146
 147                 $implicit_mentions = [];
 148                 if (($item['parent-uri'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 149                         $parent = Item::selectFirst(['id', 'author-link', 'alias'], ['uri' => $item['parent-uri']]);
 150                         if (!DBA::isResult($parent)) {
 151                                 Logger::warning('Unknown parent item.', ['uri' => $item['parent-uri']]);
 152                                 return;
 153                         }
 154
 155                         $implicit_mentions = self::getImplicitMentionList($parent);
 156                         $content = self::removeImplicitMentionsFromBody($content, $implicit_mentions);
 157                 }
 158
 159                 $item['body'] = $content;
 160                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive'], $implicit_mentions);
 161
 162                 Item::update($item, ['uri' => $activity['id']]);
 163         }
 164
 165         /**
 166          * Prepares data for a message
 167          *
 168          * @param array $activity Activity array
 169          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 170          * @throws \ImagickException
 171          */
 172         public static function createItem($activity)
 173         {
 174                 $item = [];
 175                 $item['verb'] = ACTIVITY_POST;
 176                 $item['parent-uri'] = $activity['reply-to-id'];
 177
 178                 if ($activity['reply-to-id'] == $activity['id']) {
 179                         $item['gravity'] = GRAVITY_PARENT;
 180                         $item['object-type'] = ACTIVITY_OBJ_NOTE;
 181                 } else {
 182                         $item['gravity'] = GRAVITY_COMMENT;
 183                         $item['object-type'] = ACTIVITY_OBJ_COMMENT;
 184                 }
 185
 186                 if (($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
 187                         Logger::log('Parent ' . $activity['reply-to-id'] . ' not found. Try to refetch it.');
 188                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
 189                 }
 190
 191                 $item['diaspora_signed_text'] = defaults($activity, 'diaspora:comment', '');
 192
 193                 self::postItem($activity, $item);
 194         }
 195
 196         /**
 197          * Delete items
 198          *
 199          * @param array $activity
 200          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 201          * @throws \ImagickException
 202          */
 203         public static function deleteItem($activity)
 204         {
 205                 $owner = Contact::getIdForURL($activity['actor']);
 206
 207                 Logger::log('Deleting item ' . $activity['object_id'] . ' from ' . $owner, Logger::DEBUG);
 208                 Item::delete(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 209         }
 210
 211         /**
 212          * Prepare the item array for an activity
 213          *
 214          * @param array  $activity Activity array
 215          * @param string $verb     Activity verb
 216          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 217          * @throws \ImagickException
 218          */
 219         public static function createActivity($activity, $verb)
 220         {
 221                 $item = [];
 222                 $item['verb'] = $verb;
 223                 $item['parent-uri'] = $activity['object_id'];
 224                 $item['gravity'] = GRAVITY_ACTIVITY;
 225                 $item['object-type'] = ACTIVITY_OBJ_NOTE;
 226
 227                 $item['diaspora_signed_text'] = defaults($activity, 'diaspora:like', '');
 228
 229                 self::postItem($activity, $item);
 230         }
 231
 232         /**
 233          * Create an event
 234          *
 235          * @param array $activity Activity array
 236          * @param array $item
 237          * @throws \Exception
 238          */
 239         public static function createEvent($activity, $item)
 240         {
 241                 $event['summary']  = HTML::toBBCode($activity['name']);
 242                 $event['desc']     = HTML::toBBCode($activity['content']);
 243                 $event['start']    = $activity['start-time'];
 244                 $event['finish']   = $activity['end-time'];
 245                 $event['nofinish'] = empty($event['finish']);
 246                 $event['location'] = $activity['location'];
 247                 $event['adjust']   = true;
 248                 $event['cid']      = $item['contact-id'];
 249                 $event['uid']      = $item['uid'];
 250                 $event['uri']      = $item['uri'];
 251                 $event['edited']   = $item['edited'];
 252                 $event['private']  = $item['private'];
 253                 $event['guid']     = $item['guid'];
 254                 $event['plink']    = $item['plink'];
 255
 256                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
 257                 $ev = DBA::selectFirst('event', ['id'], $condition);
 258                 if (DBA::isResult($ev)) {
 259                         $event['id'] = $ev['id'];
 260                 }
 261
 262                 $event_id = Event::store($event);
 263                 Logger::log('Event '.$event_id.' was stored', Logger::DEBUG);
 264         }
 265
 266         /**
 267          * Creates an item post
 268          *
 269          * @param array $activity Activity data
 270          * @param array $item     item array
 271          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 272          * @throws \ImagickException
 273          */
 274         private static function postItem($activity, $item)
 275         {
 276                 /// @todo What to do with $activity['context']?
 277
 278                 if (($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['parent-uri']])) {
 279                         Logger::log('Parent ' . $item['parent-uri'] . ' not found, message will be discarded.', Logger::DEBUG);
 280                         return;
 281                 }
 282
 283                 $item['network'] = Protocol::ACTIVITYPUB;
 284                 $item['private'] = !in_array(0, $activity['receiver']);
 285                 $item['author-link'] = $activity['author'];
 286                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, true);
 287
 288                 if (empty($activity['thread-completion'])) {
 289                         $item['owner-link'] = $activity['actor'];
 290                         $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, true);
 291                 } else {
 292                         Logger::info('Ignoring actor because of thread completion.');
 293                         $item['owner-link'] = $item['author-link'];
 294                         $item['owner-id'] = $item['author-id'];
 295                 }
 296
 297                 $item['uri'] = $activity['id'];
 298                 $content = HTML::toBBCode($activity['content']);
 299                 $content = self::replaceEmojis($content, $activity['emojis']);
 300                 $content = self::convertMentions($content);
 301
 302                 $implicit_mentions = [];
 303
 304                 if (($item['parent-uri'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 305                         $item_private = !in_array(0, $activity['item_receiver']);
 306                         $parent = Item::selectFirst(['id', 'private', 'author-link', 'alias'], ['uri' => $item['parent-uri']]);
 307                         if (!DBA::isResult($parent)) {
 308                                 return;
 309                         }
 310                         if ($item_private && !$parent['private']) {
 311                                 Logger::log('Item ' . $item['uri'] . ' is private but the parent ' . $item['parent-uri'] . ' is not. So we drop it.');
 312                                 return;
 313                         }
 314
 315                         $implicit_mentions = self::getImplicitMentionList($parent);
 316                         $content = self::removeImplicitMentionsFromBody($content, $implicit_mentions);
 317                 }
 318
 319                 $item['created'] = $activity['published'];
 320                 $item['edited'] = $activity['updated'];
 321                 $item['guid'] = $activity['diaspora:guid'];
 322                 $item['title'] = HTML::toBBCode($activity['name']);
 323                 $item['content-warning'] = HTML::toBBCode($activity['summary']);
 324                 $item['body'] = $content;
 325
 326                 if (($activity['object_type'] == 'as:Video') && !empty($activity['alternate-url'])) {
 327                         $item['body'] .= "\n[video]" . $activity['alternate-url'] . '[/video]';
 328                 }
 329
 330                 $item['location'] = $activity['location'];
 331
 332                 if (!empty($item['latitude']) && !empty($item['longitude'])) {
 333                         $item['coord'] = $item['latitude'] . ' ' . $item['longitude'];
 334                 }
 335
 336                 $item['tag'] = self::constructTagString($activity['tags'], $activity['sensitive'], $implicit_mentions);
 337                 $item['app'] = $activity['generator'];
 338                 $item['plink'] = defaults($activity, 'alternate-url', $item['uri']);
 339
 340                 $item = self::constructAttachList($activity['attachments'], $item);
 341
 342                 if (!empty($activity['source'])) {
 343                         $item['body'] = $activity['source'];
 344                 }
 345
 346                 $stored = false;
 347
 348                 foreach ($activity['receiver'] as $receiver) {
 349                         $item['uid'] = $receiver;
 350                         $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 351
 352                         if (($receiver != 0) && empty($item['contact-id'])) {
 353                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 354                         }
 355
 356                         if ($activity['object_type'] == 'as:Event') {
 357                                 self::createEvent($activity, $item);
 358                         }
 359
 360                         $item_id = Item::insert($item);
 361                         if ($item_id) {
 362                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 363                         } else {
 364                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 365                         }
 366
 367                         if ($item['uid'] == 0) {
 368                                 $stored = $item_id;
 369                         }
 370                 }
 371
 372                 // Store send a follow request for every reshare - but only when the item had been stored
 373                 if ($stored && !$item['private'] && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 374                         $author = APContact::getByURL($item['owner-link'], false);
 375                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 376                         if ($author['type'] != 'Group') {
 377                                 Logger::log('Send follow request for ' . $item['uri'] . ' (' . $stored . ') to ' . $item['author-link'], Logger::DEBUG);
 378                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 379                         }
 380                 }
 381         }
 382
 383         /**
 384          * Fetches missing posts
 385          *
 386          * @param $url
 387          * @param $child
 388          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 389          */
 390         private static function fetchMissingActivity($url, $child)
 391         {
 392                 if (Config::get('system', 'ostatus_full_threads')) {
 393                         return;
 394                 }
 395
 396                 $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
 397
 398                 $object = ActivityPub::fetchContent($url, $uid);
 399                 if (empty($object)) {
 400                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
 401                         return;
 402                 }
 403
 404                 if (empty($object['id'])) {
 405                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
 406                         return;
 407                 }
 408
 409                 $activity = [];
 410                 $activity['@context'] = $object['@context'];
 411                 unset($object['@context']);
 412                 $activity['id'] = $object['id'];
 413                 $activity['to'] = defaults($object, 'to', []);
 414                 $activity['cc'] = defaults($object, 'cc', []);
 415                 $activity['actor'] = $child['author'];
 416                 $activity['object'] = $object;
 417                 $activity['published'] = defaults($object, 'published', $child['published']);
 418                 $activity['type'] = 'Create';
 419
 420                 $ldactivity = JsonLD::compact($activity);
 421
 422                 $ldactivity['thread-completion'] = true;
 423
 424                 ActivityPub\Receiver::processActivity($ldactivity);
 425                 Logger::log('Activity ' . $url . ' had been fetched and processed.');
 426         }
 427
 428         /**
 429          * perform a "follow" request
 430          *
 431          * @param array $activity
 432          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 433          * @throws \ImagickException
 434          */
 435         public static function followUser($activity)
 436         {
 437                 $uid = User::getIdForURL($activity['object_id']);
 438                 if (empty($uid)) {
 439                         return;
 440                 }
 441
 442                 $owner = User::getOwnerDataById($uid);
 443
 444                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 445                 if (!empty($cid)) {
 446                         self::switchContact($cid);
 447                         DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
 448                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 449                 } else {
 450                         $contact = false;
 451                 }
 452
 453                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
 454                         'author-link' => $activity['actor']];
 455
 456                 // Ensure that the contact has got the right network type
 457                 self::switchContact($item['author-id']);
 458
 459                 Contact::addRelationship($owner, $contact, $item);
 460                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 461                 if (empty($cid)) {
 462                         return;
 463                 }
 464
 465                 if (empty($contact)) {
 466                         DBA::update('contact', ['hub-verify' => $activity['id']], ['id' => $cid]);
 467                 }
 468
 469                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
 470         }
 471
 472         /**
 473          * Update the given profile
 474          *
 475          * @param array $activity
 476          * @throws \Exception
 477          */
 478         public static function updatePerson($activity)
 479         {
 480                 if (empty($activity['object_id'])) {
 481                         return;
 482                 }
 483
 484                 Logger::log('Updating profile for ' . $activity['object_id'], Logger::DEBUG);
 485                 APContact::getByURL($activity['object_id'], true);
 486         }
 487
 488         /**
 489          * Delete the given profile
 490          *
 491          * @param array $activity
 492          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 493          */
 494         public static function deletePerson($activity)
 495         {
 496                 if (empty($activity['object_id']) || empty($activity['actor'])) {
 497                         Logger::log('Empty object id or actor.', Logger::DEBUG);
 498                         return;
 499                 }
 500
 501                 if ($activity['object_id'] != $activity['actor']) {
 502                         Logger::log('Object id does not match actor.', Logger::DEBUG);
 503                         return;
 504                 }
 505
 506                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
 507                 while ($contact = DBA::fetch($contacts)) {
 508                         Contact::remove($contact['id']);
 509                 }
 510                 DBA::close($contacts);
 511
 512                 Logger::log('Deleted contact ' . $activity['object_id'], Logger::DEBUG);
 513         }
 514
 515         /**
 516          * Accept a follow request
 517          *
 518          * @param array $activity
 519          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 520          * @throws \ImagickException
 521          */
 522         public static function acceptFollowUser($activity)
 523         {
 524                 $uid = User::getIdForURL($activity['object_actor']);
 525                 if (empty($uid)) {
 526                         return;
 527                 }
 528
 529                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 530                 if (empty($cid)) {
 531                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 532                         return;
 533                 }
 534
 535                 self::switchContact($cid);
 536
 537                 $fields = ['pending' => false];
 538
 539                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
 540                 if ($contact['rel'] == Contact::FOLLOWER) {
 541                         $fields['rel'] = Contact::FRIEND;
 542                 }
 543
 544                 $condition = ['id' => $cid];
 545                 DBA::update('contact', $fields, $condition);
 546                 Logger::log('Accept contact request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 547         }
 548
 549         /**
 550          * Reject a follow request
 551          *
 552          * @param array $activity
 553          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 554          * @throws \ImagickException
 555          */
 556         public static function rejectFollowUser($activity)
 557         {
 558                 $uid = User::getIdForURL($activity['object_actor']);
 559                 if (empty($uid)) {
 560                         return;
 561                 }
 562
 563                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 564                 if (empty($cid)) {
 565                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 566                         return;
 567                 }
 568
 569                 self::switchContact($cid);
 570
 571                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING, 'pending' => true])) {
 572                         Contact::remove($cid);
 573                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . ' - contact had been removed.', Logger::DEBUG);
 574                 } else {
 575                         Logger::log('Rejected contact request from contact ' . $cid . ' for user ' . $uid . '.', Logger::DEBUG);
 576                 }
 577         }
 578
 579         /**
 580          * Undo activity like "like" or "dislike"
 581          *
 582          * @param array $activity
 583          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 584          * @throws \ImagickException
 585          */
 586         public static function undoActivity($activity)
 587         {
 588                 if (empty($activity['object_id'])) {
 589                         return;
 590                 }
 591
 592                 if (empty($activity['object_actor'])) {
 593                         return;
 594                 }
 595
 596                 $author_id = Contact::getIdForURL($activity['object_actor']);
 597                 if (empty($author_id)) {
 598                         return;
 599                 }
 600
 601                 Item::delete(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
 602         }
 603
 604         /**
 605          * Activity to remove a follower
 606          *
 607          * @param array $activity
 608          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 609          * @throws \ImagickException
 610          */
 611         public static function undoFollowUser($activity)
 612         {
 613                 $uid = User::getIdForURL($activity['object_object']);
 614                 if (empty($uid)) {
 615                         return;
 616                 }
 617
 618                 $owner = User::getOwnerDataById($uid);
 619
 620                 $cid = Contact::getIdForURL($activity['actor'], $uid);
 621                 if (empty($cid)) {
 622                         Logger::log('No contact found for ' . $activity['actor'], Logger::DEBUG);
 623                         return;
 624                 }
 625
 626                 self::switchContact($cid);
 627
 628                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
 629                 if (!DBA::isResult($contact)) {
 630                         return;
 631                 }
 632
 633                 Contact::removeFollower($owner, $contact);
 634                 Logger::log('Undo following request from contact ' . $cid . ' for user ' . $uid, Logger::DEBUG);
 635         }
 636
 637         /**
 638          * Switches a contact to AP if needed
 639          *
 640          * @param integer $cid Contact ID
 641          * @throws \Exception
 642          */
 643         private static function switchContact($cid)
 644         {
 645                 $contact = DBA::selectFirst('contact', ['network'], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
 646                 if (!DBA::isResult($contact) || ($contact['network'] == Protocol::ACTIVITYPUB)) {
 647                         return;
 648                 }
 649
 650                 Logger::log('Change existing contact ' . $cid . ' from ' . $contact['network'] . ' to ActivityPub.');
 651                 Contact::updateFromProbe($cid, Protocol::ACTIVITYPUB);
 652         }
 653
 654         /**
 655          * Collects implicit mentions like:
 656          * - the author of the parent item
 657          * - all the mentioned conversants in the parent item
 658          *
 659          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
 660          * @return array
 661          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 662          */
 663         private static function getImplicitMentionList(array $parent)
 664         {
 665                 $parent_terms = Term::tagArrayFromItemId($parent['id'], [TERM_MENTION]);
 666
 667                 $implicit_mentions = [
 668                         $parent['author-link']
 669                 ];
 670
 671                 if ($parent['alias']) {
 672                         $implicit_mentions[] = $parent['alias'];
 673                 }
 674
 675                 foreach ($parent_terms as $term) {
 676                         $contact = Contact::getDetailsByURL($term['url'], 0);
 677                         if (!empty($contact)) {
 678                                 $implicit_mentions[] = $contact['url'];
 679                                 $implicit_mentions[] = $contact['nurl'];
 680                                 $implicit_mentions[] = $contact['alias'];
 681                         }
 682                 }
 683
 684                 return $implicit_mentions;
 685         }
 686
 687         /**
 688          * Strips from the body prepended implicit mentions
 689          *
 690          * @param string $body
 691          * @param array  $implicit_mentions List of profile URLs
 692          * @return string
 693          */
 694         private static function removeImplicitMentionsFromBody($body, array $implicit_mentions)
 695         {
 696                 if (Config::get('system', 'disable_mentions_removal')) {
 697                         return $body;
 698                 }
 699
 700                 $kept_mentions = [];
 701
 702                 // Extract one prepended mention at a time from the body
 703                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#mis', $body, $matches)) {
 704                         if (!in_array($matches[2], $implicit_mentions) ) {
 705                                 $kept_mentions[] = $matches[1];
 706                         }
 707
 708                         $body = $matches[3];
 709                 }
 710
 711                 // Re-appending the kept mentions to the body after extraction
 712                 $kept_mentions[] = $body;
 713
 714                 return implode('', $kept_mentions);
 715         }
 716 }